The IBM 4704

In 2011, while consulting with fellow enthusiasts of IBM keyboards, I was introduced to the keyboards for the IBM 4704 display terminal. This is the terminal for the IBM 4700 Finance Communication System, introduced at the beginning of the 1980s. This page details the information and resources I have been able to find about this system, notably surrounding 4704 terminals for this system and repurposing 4704 input peripherals for modern computers.

This page is written by a hobbyist for the benefit of hobbyists. I do not claim to be an expert on the topic, and welcome any additional information or corrections (use the Contact option on the menu).

4700 System Overview

The IBM 4700 Finance Communication System is, when boiled down to the basics, a mainframe-terminal arrangement designed to be used primarily for financial transactions (such as in a bank, with each teller having a terminal). This system dates to as early as 1981, and was discontinued by the early 1990s.

An example of a 4700 B-loop, downstream of the 4702 processor.

Terminal connectivity is established via a “B-loop”. This loop connects terminals and other 4700 equipment you’d find at that ‘branch’ with controller equipment which handles uplink-type communications to the mainframe which may be off-site. A number of IBM mainframe systems were supported.

IBM documentation suggests the 4700 local loop connectivity is compatible with their prior financial system, the 3600. At least some 4700 equipment can connect to a 3600 local loop, and vice-versa.

The 4704 Display Terminal

The ‘terminal’ used in a 4700 setup is the 4704. PC, XT, AT and PS/2 computers had options to enable them to act as a 4704, similar in concept to a 3270 PC.

From IBM:

The 4704 is a modular, user configurable CRT display and keyboard terminal for input and output in interactive banking applications. It provides flexibility in both workstation layout and configurations, and can be tailored to meet the needs of teller, back-office and self-service applications.

Model Differences

4704-1

First shipped in October 1982 with 50-key keyboard (62 and 77 came in December 1982)

Serial numbers 49999 and down

Connects to 4700, 3600/5995 controllers via B-loop

Sold with one of two monitors: 5.5″ 480-character (12 lines of 40), or 9″ 480/1920-character (24 lines of 80). These monitors are available with either a 15-degree tilt stand/riser, or an optional adjustable -30 to +30 degree cradle. Anti-glare filters available and display can either be monochrome yellow on brown, or bright green on dark green. Character display is a 7×9 dot matrix.

Sold with 50-key Function, 62-key Alphameric, or 77-key Expanded Alphameric keyboard. 50 and 62 can be used in conjunction with each other.

It is compatible with the magnetic stripe reader and PIN keypad.

Connectors: local loop interface on a permanently attached cable, female DA15 on a permanently attached cable for combined signal and power to the monitor, female DA15 on the unit (purpose presently unknown), C14 normal computer power cord connector, 3x female DE9 for keyboard(s) and accessories

Replaced by Model 1 Enhanced

4704-1 Enhanced

Replaced original Model 1 as of May 18 1984 – serial numbers 50000 and up with ‘A’ on the tag

Similar appearance but different dimensions compared to original Model 1: 260x222x146mm new, 259x208x137mm old

Same features as original Model 1, but adds support for the 107-key administrative keyboard and displaying which of four shift modes the keyboard is operating in.

New October 2013: I now have a 4704 monitor! I have yet to hook up the system and see what it does; likely a blank screen since there’s no loop. Part number is 6019176, manufactured 06-1984. Model designation is “100” and it was made in Japan.

4704 Keyboards

The following keyboards exist for the 4704:

50-key “function”, matrix/grid, relegendable transparent keycaps, designated “Model 100”
From IBM: “The 50-key Function keyboard is intended for teller use. Forty-five of the keys may have functions assigned by the user. These keys are clear plastic capped to enable labelling by the user. The remaining five keys are pre-engraved. The 50-key keyboard may be used alone or in conjunction with a 62-key keyboard for device functions.”

62-key “alphameric”, designated “Model 200”
From IBM: “The 62-key alphameric keyboard is intended for use by teller, back-office or administrative personnel. It may be used alone or in conjunction with the function keyboard (above). This keyboard provides full alphameric input plus limited user assigned function.”

77-key “extended alphameric”, designated “Model 300”
From IBM: “The 77-key expanded alphameric keyboard can be used in any bank function. It provides the same input capability as the alphameric keyboard but also provides a 15-key keypad on the right side of the keyboard. These 15 keys have user assigned functions and are clear-plastic capped for labelling purposes.”

In each case, the keyswitch mechanism is capacitive buckling springs. They are one of, if not the earliest example of an IBM buckling spring keyboard with “relegendable” (transparent plastic) keycaps. While not confirmed, it is possible that the 50-key 4704 keyboard is the only matrix-layout capacitive buckling spring keyboard.

4704 Keyboard Interface

Geekhack members Soarer, dfj, and hasu (among others I am personally unaware of, undoubtedly) put in considerable work in figuring out the communication protocol used by 4704 keyboards. After putting the effort in, hasu was able to come up with a functional converter to use the 4704 keyboards on a modern PC, without requiring modification to the keyboard.

You may learn more about hasu’s converter, using the unmodified keyboard, here. Hasu has more converter offerings than just for the 4704, and you can read more about them here.

Xwhatsit has also developed an internal replacement controller, which makes the keyboard natively USB HID, rather than being an inline converter using the original electronics. You may learn more about this option here.

In addition to the options described above, Soarer had another project where the original electronics could be mostly left untouched except for replacing just the main controller IC. To my knowledge, this project never took off and the other options above were preferred.

Other 4704 Peripheral Devices

Other devices which can attach directly to a 4704 include:

Magnetic stripe reader (ANSI Track 2, 75 bpi)

PIN keypad (12-key numeric keypad)

List of 4700-Series Equipment

Although I am not focusing on any other 4700 series equipment, here is a list of what I’ve been able to find and confirm, between Wikipedia, miscellaneous search results and IBM announcement letters:

Where can I find 4700 equipment?

As with most obsolete/EOL computer equipment, there are thousands of parts resellers promising they can source these items. However, most of the time, they do not have real inventory, and do not have a source that has it either. When a reseller will not divulge a price without you submitting a “request for quote” or “request for price” it generally means they don’t have the item and will go looking for it per your request.

I receive emails asking where to buy 4704 equipment. I do not know. The sources that used to have these items do not any longer, and I have not actively sought them since 2014.

Because of the massive enthusiast interest in the keyboards, following my documentation becoming public, it is near-impossible to find the keyboards for “cheap” unless you can source them directly from a reseller or recycler. Overseas (relative to North America) e-waste processing operations might be an avenue worth exploring.

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8 thoughts on “The IBM 4704”

Hi. I know it’s been a long time since this post but I’ll make the attempt. I have an IBM 4704 terminal and I am trying to identify the input cables to the 5″ monochrome display (pin out) and maybe you can help me with this.
I would really appreciate it since there is very little information on this.
Thank you

I did eventually sell the 4704 monitor, so unfortunately I can’t be of any help. I have asked the new owner if he can try to look into this, but I’m not sure if he has the lower-level electronics knowledge to figure it out. The AC power pins should be straightforward to figure out, but the video signal will be more complicated I think.

Apologies for missing that comment.
I believe I know of an individual in the US who owns one; he got it well after the “Kishsaver craze” peaked, if that makes sense. I don’t recall exactly how he got it.

The photo I used as an example of it was posted on Geekhack many years ago, if I recall correctly, as a “wtf is this” type of post.